Submandibular Approach for Tracheal Intubation –A Case Report

Summary Intubating a patient with panfacial fractures is always a challenge to the anaesthesiologist. In a 40-yr-old male patient with left Le Fort’s III fracture with nasal bone and symphysis menti fracture, we successfully carried out oral endotracheal intubation which was then modified to submandibular approach to provide adequate surgical field. Initially oral endotracheal intubation was performed, then an incision was made in the submandibular region through which the endotracheal tube was brought out and maintained as submandibular approach throughout the surgery.


Introduction
Maxillofacial surgicalpatients present a specific challenge to the anaesthesiologist. The standard oral route for trachealintubation can be unsuitable for some maxillofacialsurgeries because it can interrupt the surgical field and can interfere with teeth occlusion frequently needed for the adjustmentand fixation of maxillary fractures. 1 The nasal route can be used, however it can be impossible as a result of a deformity or fractures in nasal bone and it may interrupt surgical accessibility. Also naso-tracheal intubation is contraindicated in fractures of cribriform plate of ethmoid, which frequently accompany Le Fort II or III maxillay fractures because of potential complication of infection and the possibility of cranialintubation. The standard solution in these situations is to perform an elective short term tracheostomy before the surgery. Since there is high risk of morbidity associated with tracheostomy an alternative method is to introduce a tracheal tube via a submental incision which was first introduced by Sir Hernandez Altemir in 1986. 2,3 Thesubmandibular intubationwhich wehave performed isa modificationof submentalintubation andis a betteralternativemethodfor shortterm tracheostomy. 4

Case report
A 40-yr-old ASAgrade III male patient had met witha roadtraffic accident and sustainedpanfacial fractures. He was evaluated by the maxillofacial surgeons and posted for open reduction and internalfixation of the fractures.
His pre-anaesthetic evaluation revealed history of loss of conciousness for a brief period of less than five minutes withno history of vomitingor seizures. He had no other significant medical or surgicalillnesses. On examination he was a moderately built and nourished middle aged male patient with stable vitals and normal cardiovascular and respiratory systems. He was conscious and oriented to time, place and person. His airway assessment revealed a restricted mouth opening of one and half fingers (due to pain). Mallampatti scoring couldn't be assessed because of restricted mouth opening. The temporomandibular joint mobility was restricted. Both the nares of the patient were patent with bilateral equal free flow of air on forced expiration. His laboratory investigations revealed a normal hemogram and coagulation profile. X-rays were suggestive ofmaxillary, nasaland symphysisfractures. CT also suggested the same.
We planned for submandibular approach for endo-tracheal intubation after discussing with oromaxillo-facial surgeon. The procedure was explained to the patient and his relatives in their own native language and written informed consent was obtained. Standby for possible tracheostomy inthe event of any emergency was available.
In the operating room 18 gauge IV cannula was secured in theleft arm. MonitoringincludedECG, pulse oximeter and non-invasive blood pressure.
Glycopyrrolate 0.2mg, ondansetron 4mg, pethidine 60 mg were administered intravenously as premedication.Patient waspreoxygenated with100% oxygen for 3 minutes and anaesthesia was induced with th io penton e sodium 300mg intravenously. Suxamethonium 100mgintravenouslywas administered as the musclerelaxant forintubation and intubated with 8.0 mm ID flexometalliccuffed endotrachealtube, connected to Bain's circuit. The tube was secured in place after confirming bilateral equalair entry(Fig1). Throat was adequately packed. Anaesthesia was maintained with 60% nitrous oxide, 40% oxygen and halothane 0.5 -1%. Controlled ventilation was facilitated by vecuronium bromide. submandibular area, about 1 inch below and half an inch anteriorto the angle of the mandible. This distance from the lower border of the mandible was to avoid an injury to the mandibular branch of the facialnerve. Usinga curved artery forceps, blunt dissection was carried out through the skin incision in the upward direction towards the oral cavity. The subcutaneous fat, platysma, investing layer of the deep cervicalfascia and the mylohyoid muscle weredissected untilthe tip of the arteryforceps tentedthe mucous membrane of the oral cavity. The end of the pilot balloon of the endotracheal tube cuff was grasped with the tip of the artery forceps and then pulled through the dissected track to come out through the submandibular incision. The tracheal tube then disconnectedfrom Bain's circuit and its tube connecter was removed. Under direct vision using the laryngoscope and with the tube supported in the oropharynx by the tip of the assistant's index finger, the end of the trachealtube was grasped by the tip of the artery forceps and pulled out through the submandibular incision, in the same way as the pilot balloon of the endotrachealtube cuff. The tube was supported in the oro-pharynx throughout to prevent accidentalextubation or inward pushingof the tube. Any blood present was suctioned and throat pack was changed to a fresh one.After checkingthetube position,a markwas made on the tube at the skin exit site. A silk stay suture was made to fix the tube to the skin in the submandibular region (Fig 2). The tube was further secured by adhesive tape applied circumferentially. Anaesthesia was

Fig 1 After oral intubation
Subsequently the surgeon created a track from the oralcavity extendingto the submandibular region. The side of the submandibular area used was dictated by the presenceof mandibularfracture, howeverin our case, right side was preferred as the patient had left sided fractures. A 1.5 cm transverse skin incision was madein the At the end of the surgery, the stay sutures and adhesive plaster fixingthe tube were removed and tracheal tube was pulled back to the oralcavity, followed by the pilot tube. The submandibular incision was sutured and bandaged. In our patient, the oral endotracheal tube was retained post operatively and subsequently extubated.

Discussion
The submental route for tracheal intubation was first introduced by Sir HernandezAltemirin 1986 2 .This technique provides a secure airway whilst at the same time allowingan unobstructedsurgicalfieldfor adequate reduction and fixation of midface and panfacial fractures. 5,6 Submental trachealintubation also avoids the potential complications associated with nasal intubation and tracheostomy. 3 Stolldescribed a similar technique to submental intubation but wherethe incision is placedfurther posteriorly in the submandibularregion andProchno reported 14patientswho underwentsubmanbulartransmylohyoid intubation. 7 Submandibularintubation isa modification of submental intubation. It was found tobe an easy and convenienttechnique whichavoids thepotentialcomplications of submental approach like, damage of sublingualand submaxillary ducts,sublingualglandand lingual nerve.Pulling theend ofthe tube through thedeep cervical fascia in the submandibular area may probably be easierthan in the tight submental area 1 .
It hasbeen foundthat some of the armoured tubes (Fig 3) have connectors not designed to be removed.
The end of such tubes has to be cut off and when reattached forms a loose connection. More recently armouredtubes havinga connectorthatisspecifically designedfordetachmentandre-attachmentareavailablemakingit idealfor submandibulartrachealintubation.
Partial dislodgement of the submandibular tube, wherein the tube being pushed down the right main bronchus, bleeding and skin infection are some of the complications that have been reported.
The position of the tube being pushed down the right main bronchus is probably due to the tube not being secured properly to the skin. Partial extubation of the tube was a commondocumented complication. Securing the tube byboth circumferentialadhesive tape andskin sutures and bydoingthe submandibular positioning of the tube under direct laryngoscopic vision prevented the above complications.
Studies report submandibular tubes to be converted to oral tubes at the end of surgery and most of them extubated at the theatre. Delayed oral extubation in the intensive care unit also is reported because of associated facial injury. In our patient also because of the facial swelling and edema of the oral cavity, tube was retained post-operatively and extubated subsequently in the intensive care unit.
In conclusion, the submandibular method is a novel, alternative method for tracheal intubation in patientswith craniomaxillo-facialinjuries coming for surgery. It is a low morbidity technique, avoids the complication that occur with tracheostomy and nasal intubation. The procedure has minimalcomplications and patient's airway is not compromised.